Entry Type ID Date Applicable Rating System Primary Credit Inquiry (LIs) Ruling (LIs) Related Addenda/LIs Related Resources Campus Applicable Internationally Applicable Country Applicability Reference Guide (Addenda) Page (Addenda) Location (Addenda) Description of Change (Addenda) "Reference Guide Correction" "100000639" "2009-10-27" "Homes" "None" "None" "Homes, 2008 edition" "324" "Column 2, 4th paragraph" """If tests for radon are positive, install an active radon mitigation system... below the house."" change to ""If tests for radon are positive, install an active radon mitigation system... below the house. After the mitigation system is installed, re-test for radon to ensure that the system is functioning properly to remove radon.""" "Reference Guide Correction" "100000640" "2009-10-27" "Homes" "None" "None" "Homes, 2008 edition" "324" "Column 2, last paragraph" """For gut rehab projects, use radon-resistant construction for existing buildings, as per ASTME-2121 (see www.epa.gov/radon/pubs/mitstds.html)."" change to ""Gut-rehab projects should use the new residential construction guidance in EPA\'s Indoor airPLUS, or existing residential buildings language in ASTME-2121. Post-occupancy tests are strongly encouraged. See www.epa.gov/radon/pubs/mitstds.html.""" "LEED Interpretation" "10168" "2012-04-01" "Homes" "This project is proposing to meet the requirements of EQ 9 in the following way: \nThe homes will be constructed with a structural basement floor. This floor is supported by the foundation walls and creates a ""crawlspace"" below the basement. The crawlspace is approximately 18""-24"" tall, and there is a 10 mil poly barrier directly on the soil. The poly is lapped up onto the foundation wall approximately 10""-12"" and is sealed to the concrete face of the wall. All seams in the poly are also lapped and sealed. Additionally all the poly is sealed to all penetrations such as pipe columns and the sump pit. The sump pit remains in the crawl space and does not extend into the basement. \nThe basement floor has a number of transfer grills in the floor, sized to allow a specific volume of air to pass thru them. A continuous duty rated in-line fan is installed in a 6"" diameter pipe the connects the crawlspace to the exterior of the home. As the fan operates it draws air from the crawlspace and vents it directly to the exterior. A negative pressure is created in the crawlspace that promotes the movement of air from the positively pressurized basement, thru the transfer grills and into the crawlspace. The movement of air is always from the basement to the crawlspace. There is no air exchange from the crawl space to the basement. Unless something malfunctions, the fan can never be shut off. It is hard-wired to run continuously. The system is equipped with an alarm system where if the fan does malfunction, an alarm will sound and something will have to be done to fix it.\nThe builder will include detailed information about the purpose of the fan, and importance of not ripping the 10 mil poly with regards to radon mitigation, in the homeowner booklet and during the walkthrough." "The proposed approach is acceptable for meeting the requirements of EQ 9. " "None" "None" "LEED Interpretation" "10169" "2012-04-01" "Homes, Mid-rise" "Is there a requirement related to the placement of the junction box?" "The junction box should be located close to the exit point of the radon pipe, so it could serve a vent fan if one is determined to be necessary. EPA guidance suggests that any radon exhaust fan should not be located in living spaces. Updated 10/1/13 for rating system applicability. " "None" "None" "LEED Interpretation" "10173" "2012-04-01" "Homes" "In projects with multiple attached homes, how should radon be handled? Must each individual unit have separate radon system, or is it acceptable to have a large radon system serving all of the homes?" "Projects with multiple single-family attached homes may meet EQ 9 in one of two ways:\n1) install a separate radon resistant new construction system in each home - with separate below-grade pipes, separate pipe stacks, separate junction boxes, etc.\n2) treat the project like a multi-family building (see EQ 09-20), but with the added requirement that some legal language must exist that enables any homeowner to activate the radon system if he/she finds evidence of high radon levels. " "None" "None" "LEED Interpretation" "1336" "2006-01-01" "Homes" "Can this prerequisite be satisfied with mechanical ventilation in the basement or crawl space?" "No. A typical exhaust only ventilation system does not meet the requrements for Radon Resistant New Construction (RRNC). In fact, exhaust only mechanical ventilation may increase radon concentrations indoors. RRNC requires a capilary break beneath the slab, a vent stack from below the slab to above the roof line, and provision for installation of a radon-rated exhaust fan (if needed). Applicable Internationally. " "None" "None" "X" "LEED Interpretation" "1900" "2007-09-05" "Homes, Mid-rise" "For buildings constructed over an open-air garage, is EQ 9 satisfied automatically?" "Yes, if the building is constructed over a completely open-air garage, the requirements for EQ 9.1 or 9.2 are satisfied. Updated 10/1/13 for rating system applicability. " "None" "None" "X" "LEED Interpretation" "2013" "2008-02-05" "Homes, Mid-rise" "For an active radon mitigation system, is there any reason the inline fan couldn\'t be located in the basement mechanical room as opposed to the attic, if it was necessary? I will check the EPA web site but thought you may have come across this before." "To be clear, a fan is not required as part of EQ 9.1 - it only refers to passive radon resistant construction techniques. Applicable Internationally. \n\nGenerally, it is best practice to have the fan at the edge of the envelope to prevent pressurizing the exhaust pipe, which can create a greater risk of radon entry into the home in the event of a system leak. Having the fan outside the envelope can increase the risk of failures, especially in cold climates. In every case, the fan should be in a place that is accessible, in case of failures. Once a fan is installed, be sure to seal the exhaust pipe and test for leaks. Refer to the EPA site and the EEBA Guides for more information. Updated 10/1/13 for rating system applicability. " "None" "None" "X" "LEED Interpretation" "2140" "2008-05-06" "Homes, Mid-rise" "For multifamily buildings constructed over an enclosed garage, can EQ 9 be satisfied with continuous exhaust in the garage? If so, what is the required exhaust rate?" "Yes - a multifamily project constructed over a multi-car ventilated garage (active or naturally ventilated) that meets ASHRAE 62.1-2007 garage ventilation requirements is considered radon resistant construction. Updated 10/1/13 for rating system applicability. Updated 10/1/14 to allow ventilated garages of any kind to be considered radon resistant construction " "None" "None" "X" "LEED Interpretation" "2217" "2008-06-09" "Homes" "Is RRNC required for a home that is built on concrete piers with the enclosed envelope of the house a good 2 feet above the ground. The space between the house and the ground is completely open and continuously vented to outside air. All penetrations of the floor are sealed to the outside (SIPS panels used). " "If the home is raised above the ground by 2 feet and the space is completely open to the outside such that there is continuous air flow, then radon resistant new construction is not needed. EQ 9.1 is waived, and if the home is in EPA Radon Zone 2, the home can earn credit for EQ 9.2." "None" "None" "LEED Interpretation" "2453" "2008-12-15" "Homes, Mid-rise" "Does the vent pipe need to go all the way to the roof? Is it good enough to have it capped tightly and labeled?\n\nThe project plans to use the following strategy for radon mitigation:\n\nThe sub slab meets the requirements of radon resistant construction, including a 6mm plastic lining, a gas permeable layer and a sealed foundation. The vent pipe is capped tightly and labeled, but it does not go all the way through the roof. We could have taken the pipe through the roof if needed but didn\'t want to put more holes than needed in the roof, especially with a 10 kW solar up and under-roof solar thermal to deal with. I don\'t think a normal builder would want to do this until tests showed that radon was a problem either. We had Mid-Atlantic Associates, a third-party environmental consultant, perform indoor air quality samples to test for radon, among other pollutants. Tests showed that radon were well below levels of concern. These are attached." "Radon-resistant new construction requires the sub-slab pipe to be vented to the outside, either through the side wall or roof. It is not acceptable to cap the pipe inside the home. Updated 10/1/13 for rating system applicability. " "None" "None" "LEED Interpretation" "2608" "2009-07-16" "Homes, Mid-rise" "Canada does not have radon risk maps such as those developed by EPA and used to determine whether a project is or is not in EPA zone 1 and therefore whether or not it must install a radon mitigation system or has the option of doing so to earn a point under the rating system. Since there is no map & no way to assess risk, is the project eligible for a point if a radon mitigation system is installed?" "The prerequisite in Canada is to have the home tested for radon OR install radon resistant new construction. In order to earn 1 point, an active sub-slab or sub-membrane depressurization system must be installed. Applicable Internationally; Canada. \n Updated 10/1/13 for rating system applicability. " "None" "None" "X" "LEED Interpretation" "2609" "2009-07-16" "Homes, Mid-rise" "Prior CIRs have indicated that radon testing may be required in some cases and strongly recommended in others. What is the protocol for testing for radon?" "USGBC follows the EPA recommendations on radon testing. Please see www.epa.gov/radon/pubs/citguide.html for details. \n\nEPA guidance includes 3 steps: 1) Take a short-term test. If the result is 4 pCi/L or higher, go to step 2; 2) Follow-up with either a long-term test or a second short-term test. 3) If you followed up with a long-term test and the result is 4pCi/L or more, then mitigation is required; if you followed up with a second short-term test and the average of the two tests is 4 pCi/L or higher, then mitigation is required. \n\nIf a mitigation system is required and installed, the project must undergo testing following the steps above to confirm that the mitigation system is operating as needed. If two short-term tests report 4 pCi/L or more, consult a radon expert to fix or improve the radon mitigation system, then repeat all previous steps again.\n\nFurther EPA guidance: \n Updated 10/1/13 for rating system applicability. " "None" "None" "LEED Interpretation" "2638" "2009-06-01" "Homes, Mid-rise" "For projects in Radon Zone 1, if there is a 3rd party testing to show that there is not a Radon issue in the area - can the prerequisite be skipped?" "Radon cannot be tested for prior to construction, so homes in EPA Zone 1 must have radon-resistant construction. For homes that overlook this prerequisite, project-specific CIRs may be submitted and post-construction radon testing may be allowed as an alternative. Updated 10/1/13 for rating system applicability. " "None" "None" "LEED Interpretation" "2716" "2009-11-24" "Homes, Mid-rise" "What are the minimum components required to satisfy the radon resistant new construction requirement? The Reference Guide and V&S Guidelines include slightly different guidance." "Radon-resistant new construction includes five components: 1) gas-permeable layer; 2) heavy-gauge plastic sheeting; 3) sealing and caulking of all penetrations through the concrete slab; 4) vent pipe to exhaust gases to the outside; and 5) electrical outlet near vent piping. \n\nA exhaust fan is not required, but the electrical outlet is designed so a fan can be added later if needed. Updated 10/1/13 for rating system applicability. " "None" "None" "X" "LEED Interpretation" "2767" "2010-01-19" "Homes, Mid-rise" "If there are regional or state maps that indicate that radon is a ""high"" risk, should those maps supercede the EPA Radon Zone map?" "No - EQ 9.1 only applies for projects that fall in Zone 1 on the EPA Radon Zone Map. Updated 10/1/13 for rating system applicability. " "None" "None" "LEED Interpretation" "2768" "2010-01-19" "Homes, Mid-rise" "Can EQ 9.2 be earned by a project that is located in EPA Radon Zone 3? The title of the credit is ""Radon Construction in MODERATE Risk areas"" - which refer to Radon Zone 2 - but the content of the Rating System says ""If the home is outside EPA Radon Zone 1"", which would include Radon Zones 2 and 3." "Yes, EQ 9.2 can be earned by any project located in EPA Radon Zones 2 or 3. Updated 10/1/13 for rating system applicability. " "None" "None" "LEED Interpretation" "2802" "2010-05-18" "Homes, Mid-rise" "Are there any special requirements related to radon-resistant new construction for multi-family buildings?" "The basic elements for RRNC are the same in multi-family buildings - see EQ 09-16 for details. Multi-family projects should follow the ASTM-E Standard 2121 for details about how to design the sub-slab soil-gas collection system. See http://www.epa.gov/radon/pubs/mitstds.html for information on how to get a free copy of the Standard. Updated 10/1/13 for rating system applicability. " "None" "None" "LEED Interpretation" "5396" "2009-10-14" "Homes, Mid-rise" "How should gut-rehab projects meet the requirements in EQ 9.1?" "Gut-rehab projects must do one of the following:\n1. Meet the requirements in ASTME-2121 (See www.epa.gov/radon/pubs/mitstds.html), which includes: install passive radon-resistant infrastructure, including piping through slab that connects to exterior through sidewall or roof. In this case, the area under the slab must be tested for connectivity, to ensure the piping accommodates the entire sub-slab area. Depending on sub-slab connectivity, multiple source pipes may be needed. In this case, a post-construction test is still strongly recommended.\n2. Conduct radon testing (see EQ 09-15 for details). If the test shows minimal radon risks, no further action is required. If the test shows an unacceptable radon risk, an active radon mitigation system is required. Updated 10/1/13 for rating system applicability. " "None" "None" "X"